This was my 2nd stay at the hotel. The positive things are that the property is beautiful, the room was comfortable, you can walk to the lake, and you can walk to multiple bus stops that take you downtown in minutes.
The bad deal breakers:
1 - staff doesn't tell guests about deals they have with partners at the lake/beach
2 - breakfast is good, but expensive
3 - restaurant staff are difficult to find & not around when you need them
4 - you have to fight to get parking. If you get a spot, don't give it up, take the bus
5 - On day 2 we left a sign on the door asking for the room to be made. We left at 10am and returned at 15:30 to find the room had not been made, so we had to call down for new towels
6 - on day 3 we put up the do not disturb sign so we could take an afternoon nap. Hotel staff woke us up calling on the phone to ask if we wanted the room made, which ignored the Do Not Disturb sign we deliberately hung on the door.
I stay at a lot of hotels across Europe and in Austria for work and pleasure. This hotel drops the balls on service and that is something that you just can't forget. It will be my last stay at this hotel. My next time in Klagenfurt an Woertersee, I'll stay somewhere else.